Recently so-called smart lighting drivers are used in connected light emitting diode (LED) lighting systems. Such smart drivers are often called Sensor Ready (SR) because they include a self-powered DALI interface. This self-powered DALI interface, namely an SR interface, may be used to communicate with, and supply power to, an external device such as a wireless sensor or Outdoor Lighting Controller (OLC). The smart driver communicates to the lighting network through SR interface and the external device which connected to it.
In some connected systems, a simple wireless sensor can be fully powered by the SR bus. However, for more complicated control units such as an OLC, usually higher power or DC voltage different from the SR bus voltage is required. In that case an auxiliary low voltage power supply is also provided by the smart driver to meet this requirement.
The SR bus is connected to devices using the DALI protocol for communicating, i.e. the SR bus is pulled low periodically during the transmission of a DALI command. When the SR bus is pulled low it is equivalent to short-circuiting the SR bus. To limit this short-circuit current, a current limiter from the SR supply to the SR bus is needed. Furthermore, for different applications or different working conditions in a particular application, the SR supply and auxiliary power supply, which are located on the low voltage secondary side of the lighting driver need the capability of being enabled or disabled by a main controller in the lighting driver, which is usually on the high voltage primary side since most of the controls are located there.
Thus, it would be desirable to provide a lighting driver and associated method of operating a lighting driver which may communicate power or voltage enabling and disabling commands from a control unit on the “primary side” to both a DALI supply and auxiliary power supply on the “secondary side” of a sensor ready LED driver in a simplified manner.